Which of the following protocols enables an amateur station to transmit through a repeater without using a radio to initiate the transmission?

Explanation

EchoLink permits a licensed amateur to connect from a computer or smartphone application directly into a linked node or repeater, so the transmission originates from software rather than from the user's own transmitter. IRLP requires a radio to access the node, and D-STAR and DMR are digital voice standards rather than internet access protocols.